Refrigerating apparatus



April 20, 1954 M G SHOEMAKER 2,675,684

REFRIGERATING APPARATUS Filed Aug. 17, 1951 Patented Apr. 20, 1954UNITED sinral oFFlcE REFRIGERATNG APPARATUS Malcolm G. Shoemaker,Doylestown, Pa., assignor to Philco Corporation, Philadelphia, Pa., acorporation of Pennsylvania 6 Claims.

The present invention 'relates to refrigerating apparatus and, moreparticularly, to `a refrigeration system and valve lmeans vthereforwhich provides for vheating of the evaporator 'to ei'ect removal offrost which, during normal operation plcatin, Serial N0. 189,183, 'ledOctober 9, 1950,

now Patent No. 2,631,441, issued lviarch 17, 1953.

In accordance with the `teachings of 'my abe-ve Videntied zo-pendingapplication, deirosti'ng is a'cen'iplish'ed 'through the agency of a'valve Structure disposed 'the suction line and having connection withthe discharge side of the cor`npres'sor. This valve structure isadapted, through suitable passage means, to by-pass the main rior-frestrictor or capillary tube and, concurrently, to establish flow ofrefrigerant from said discharge side of the compressor, through thesuction line and thence through the evaporator in a direction reversewith respect to the normal direction of flow through said evaporator.The system includes a continuously open return passage or connectionwhich, under defrosting conditions, conducts liquid refrigerant flowingfrom what is ncrmally the inlet side vof Vsaid evaporator, direotiy backto the compressor.

It is an important object of the present invention to improve theconstruction and operation of the valve structure which 4is incorporatedin a system of the above mentioned type to control the 'reversal of theow of refrigerant through the evaporator. Broadly, this object oftheir'ivenw tion is realized by providing an improved valve arrangementwhich is associated "with the refrigeration system in a novel manner 'soas 'to operate directly in response to pressure conditions which arecreated in the system by initiation and termination of a defro'stingcycle. A valve arrangen ment constructed Yand used in accordance withthis invention, has the advantage of doing away with the vneed of'employing specially and 'accurateiy designed mechanical pressureapplying and compensating means, such as a spring, to govern theactuation of the valve in its fiow controll'ing function. As a result,adequate operatio'n of the valve is assured and is not jeopardized bypossible failure of mechanical vspring means.

The 'novel features of the invention and the manner in which the aboveare recited and other objects and advantages are best achieved, will'clearly appear trom the following description 'of the embodiment "shownin the accompanying drawing, which:

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Figure 1 is a diagrammatic representation of a refrigeration systemincluding de'frost'ing apparaf tus embodying the present invention andshowing the condition which exists in the system during a normalrefrigerating cycle;

Figure 2 is a View similar to Figure 1, but shows the condition whichexists in the system during 'a defrosting cycle; and

Figure 3 is an enlarged cross-sectional view of the pressure responsivevalve constructed in accordance with the invention to control the flow"of refrigerant in the system illustrated in Figures l and 2.

With more particular reference to the drfawmg, the embodiment asillustrated in Figures 1 and I2, comprises the usual elements of areirigeration system or conventional type, namely, Va motorcoinpressorlo, a condenser Il, and an evaporator i2. These elements are Vconnecfted`in series flo'w circuit through the agency of suitable connections andconduits, including iiow restrictor or vcapillary tube I3 and suctionline it. A's 'is customary, the evaporator is disposed in heat exchangerelation with a compartment or Zone to be cooled, said compartment orzone being diagrammaticallyshown by broken line C. Also, as iscustomary, the capillary tubeand the suction line may, if desired, beassociated in heat eX- change relation. This y'association has* beenomitted from the drawing in the interest oi siniplicity and clarity ofillustration.

In addition to the above mentioned usual components, the systemaccording to the inventior1,'

with the inlet of the 'evaporatoijat'itsjunctui-e with the outlet or"the iiow restri eterV orA capillary tube, and the other end connectedwith the suc'- tion line at a point Ybetween the motorcornpres'sor andthe pressure responsive valve device. y

The solenoid valve device comprises a body l providing two chambers 2oand 2l which are adapted to communicate with each other through theopening 22 (see Figure 2') in 'a valve seat structure 23 which separatesvsaid chambers. Communication between said chambers nore mally prevented(see Figure 1) by means ofk a valve element 24 in engagement with saidseat 23e. The 'valve body i9 is provided with three ports 25. 25 and 21.Ports 25 and 26 open into one chamber 2S of the valve body; one port 25being connected with the outlet of the condenser, the other port 2tbeing connnected with the inlet of the capillary tube. The remaining orthird port 2 opens into the other chamber 2| and is connected with theaforementioned connecting conduit I7 which leads to the pressureresponsive valve device I6.

The pressure responsive valve device comprises an elongated body 28which, as clearly seen in Figure 3, has a longitudinal bore 29 extendingtherethrough. One end of the valve body is provided with an enlargedportion 39 which is generally cup-shaped and is closed by means of a capEl. This cup-shaped portion and its cap cooperate to form a hermeticallysealed housing enclosing a diaphragm 32 which stretches across saidhousing, the marginal edge portion 33 of said diaphragm being lixedlyretained between at clamping surfaces 3d and 35 provided on saidcup-shaped portion and cap, respectively. A valve stem 3l having one endrigidly affixed, as at 38, to the center of the diaphragm, depends fromthe latter and extends into the bore 29 in the Valve body. The valvestem is provided with a passageway 39 which, as shown at iii), is inopen communication with space li defined by the valve cap and thediaphragm and which, as shown at d2, is also in open communication witha chamber 133. This chamber is conveniently formed by enlargement of aportion of said bore 29 and is in open communication with space dridefined by the cup-shaped portion and the diaphragm. For the purpose ofestablishing open communication between said chamber 43 and said spaced4, the aforementioned bore 25 is of greater cross-sectional dimensionthan the cross-sectional dimension of the valve stem. The chamber 43also communicates, as at d5, with another chamber 46 which is providedby a still greater enlargement of the internal bore in the valve body28. The communication between chambers d3 and 46 is controlled by meansof a valve element il which is provided on the valve stem 3l and whichis adapted for engagement with a valve seat 48 between said chambers.The valve body is 'provided with three ports 49, and 5E; port 49 opensinto chamber 43 and is connected with the suction line I d extendingfrom the evaporator; port 50 opens into chamber d5 and is connected withthe suction line portion indicated at I da which leads to themotor-compressor; and port 5I opens into space 44 and is connected withthe conduit I which, as hereinbefore indicated, is connected with thevalve controlled chamber 2| in the solenoid valve body.

Referring again to Figures 1 and 3, it will be seen that the system isconventional insofar as the normal refrigeration cycle is concerned.During such normal refrigerating cycle, the solenoid valve element 24,as seen in Figure 1, engages its valve seat 23, and the pressure valveelement di, as seen in full lines in Figure 3, is moved away from itsseat 48. Under these conditions, hot gaseous refrigerant is deliveredfrom the compressor to the condenser where the compressed gaseousrefrigerant gives up heat to the ambient air and is converted to liquidstate. From the condenser, liquefied refrigerant passes into chamber 2oof the solenoid valve body I9 and thence flows through the capillarytube i3 and the evaporator I2 where the refrigerant vaporizes and, inthe process, absorbs heat from air Within the oompartmentor zone C.Heat-laden `vaporized refrigerant which flows from the evaporatorthrough suction line lli, passes through intercommunicating chambers 43and is in the pressure valve body 28 and then flows through the suctionline portion Ilia into the compressor. During the above describedrefrigeration cycle, no flow of refrigerant occurs through conduit I1since this conduit is sealed-ol by the solenoid valve element 2d, andthe flow through the pressure valve takes place through suction linesection Id, intercommunicating chambers d3 and 65, and suction linesection Ilia. Under these conditions, it will be understood that thepressure in chamber 153| determines the pressures which exist onopposite sides of the diaphragm since said chamber is in opencommunication with cavities or spaces il and M through bore 29 andpassage- Vway 39, respectively. Thus the pressures which prevail in saidchambers and in said cavities are substantially the same so that thediaphragm is maintained in neutral position and the valve element 4ltends to remain in open position as long as the normal refrigeratingcycle is in progress, that is to say, as long as the conditionrepresented in Figure 1 exists. It is pointed out that during thisrefrigerating cycle or condition, the continuously open by-passconnection I8 performs a useful function in that fiash gas from thecapillary tube is returned to the compressor, rather than passingthrough the evaporator where such ash gas tends to reduce theeffectiveness of the evaporator. As shown in the illustrated embodiment,separation of the flash gas is conveniently accomplished by means of aseparator device 52 interposed at the outlet of the capillary tube, theinlet of the evaporator and the inlet of said by-pass conduit I3. It isignicant to note that the conduit or connection I8 is made as arestrctor. In practice, the restriction of this conduit or connection isjust sufcient to prevent liquid refrigerant passing out of the capillarytube from flowing backwardly through said conduit or connection, and toinsure that such liquid refrigerant will flow through the evaporator asis required during normal refrigerating operation of the system.

When it becomes desirable or necessary to defrost the evaporator, therefrigerating cycle is terminated and a defrosting cycle is `initiatedby mere actuation of the solenoid valve device to open the communicationbetween chambers 2i! and 2i in the body I9 of said valve device. In theembodiment shown, actuation of the solenoid valve is accomplishedthrough the agency of a solenoid coil 53 which operates to causemovement of the valve element 24 away from its seat. Operation of thissolenoid coil can be obtained through suitable control mechanisms. Suchmechanisms are generally known in the art and since the presentinvention is not concerned with them, illustration and description oftheir construction and operation is not required herein.

The condition which exists in the system during a defrosting cycle, isbest understood by referring to Figures 2 and 3. The high pressurerefrigerant emerging from the condenser into chamber 2o in the solenoidvalve body I9-, passes into chamber 2l and out through conduit I'I intospace 34 in the pressure valve body 28. The admittance of high pressurerefrigerant into the space @il results in displacing the diaphragm 32,as is represented in broken lines in Figure 3. This displacement o f thediaphragm causes movement of the valve stem 37 which brings thevalveelement 137 in engagement Withitsseatdd, therevby 'sealing communicationbetween chambers 43 and Lit in the pressure valve body. From the space44, the refrigerant passes through the bore 29 4about the valve steminto chamber 23 and, thence, enters the evaporator through line I4. Incirculating through the evaporator, the gaseous refrigerant condensesthus providing the necessary heat for lmelting the frost accumulated onsaid surfaces. From the evaporator, the refrigerant returns throughconduit I8 and suction line 'section [da to the compressor. It will beunderstood that in order to prevent mechanical diiiiculties due toliquid directly entering the compressor pump, the system utilizes thewell known type of compressor in which the space Within the shell ordome of the compressor is included in the low pressure side of thesystem. By vusing this type of compressor, the refrigerant which is inliquid state, due to the condensation occurring within the evaporatorduring defrosting, is reconverted to gaseous state by heat exchangetaking Vplace within the low pressure shell before entering thecompressor pump. It is of importance to note that the restricted borev29 impedes the flow of refrigerant which passes from of course, is thatthe opposite sides of the dia- -`fphragm 32 are subjected to therequired pressure differential to insure maintenance of the valve inclosed position, as is illustrated in broken lines in Figure 3, so longas the condition represented in Figure 2 exists.

When the defrost cycle is completed, the solenoid coil 53 isde-energized, for instance, by means of suitable known control (notshown), to move the valve element 24 in engagement with its seat.Seating of this valve element seals ofi the communication betweenchambers 2li and 2| and interrupts the fiow of high pressure refrigerantthrough conduit I1, whereupon the pressures on the opposite sides of thediaphragm equalize since sealing-off of said conduit cuts out the sourceof high pressure to cavity fill. The diaphragm then is free to return toits normal position and to release the Valve element 41 for movement toopen position under influence of the pressure difference between chamber43 and chamber 46. With opening of said valve element the pressuresthroughout the valve, that is the pressures in chambers d3 and t and incavities 4l and B4, equalize and the normal refrigeration cycle isrestored.

From the foregoing description, it will be appreciated that the presentinvention provides a defrosting system which is characterized by unusualconstructional simplicity and operational reliability. Particularly, itwill be appreciated that the peculiar construction of the pressure valveand its novel association in the system are significant features of theinvention, and that these features make it possible effectively t0control the refrigerating and the defrosting operations without havingto depend on intricate mechanical means for such operations.

I claim:

1. Means operable to control the ow of refrigerant through theevaporator of a refrigera- 6 tion-system of the type having acompressor, condenser `and a restrictor in series ilow circuit vwith'the evaporator, comprising a valve body having two intercommunicatingchambers one of which is adapted for connection with the 'outlet of theevaporator `and the other of which is adapted for connection with theinlet of the compressor, a pressure operated diaphragm enclosed in saidvalve body, a valve member carried by said diaphragm and operable toestablish and to prevent communication between said chambers, passage`means establishing communication between one side of said diaphragm andthat one chamber 'which is adapted for connection with the outlet of theevaporator, other passage means establishing communication between theother side of the ydiaphragm and said one chamber, and selectivelycontrollable conduit means communicating with said one chamber andadapted for connection with the condenser to establish communicationbetween the latter and said one chamber.

'2. Control means as set forth in claim 1, in which the first mentionedpassage means is constructed as a restrictor.

3. En combination with a refrigeration system of 'the type having acompressor, a condenser, a restrictor an evaporator; means operable tocontrol the flow of refrigerant through the evaporator comprising avalve body having a first chamber 'connected with the outlet lof theevaporator and a second chamber connected with the inlet of thecompressor, a pressure operated diaphragm enclosed in said valve bodyand cooperating with portions thereof to denne a first cavity to oneside of said diaphragm and a second cavity to the other side of saiddiaphragm, a valve member connected with said diaphragm and normallypositioned to establish communication between said chambers, rst meansestablishing open communication between said first cavity and said firstchamber, second means establishing open communication between saidsecond cavity and said first chamber, and selec-` tively controllablemeans operable to connect said first cavity with the condenser toprovide for admission of refrigerant at high pressure in said cavity tocause movement of said diaphragm and valve to a position preventingcommunication between said chambers, said flrst means being soconstructed as to impede the flow of refrigerant from said rst cavity tosaid first chamber to provide for reduced pressure in said chamber whenthe latter is connected with the condenser.

4. In combination with a refrigeration system of the type having acompressor, a condenser, a restrictor and an evaporator; means operableto control the now of refrigerant through the evaporator comprising avalve body provided with two intercommunicating chambers, onecommunicating with the outlet of the evaporator and the othercommunicating with the inlet of the compressor, a diaphragm enclosed insaid body and cooperating with portions thereof to deiine a cavity toone side ci" the diaphragm and a cavity to the other side of thediaphragm, selectively controllable communication means between one ofsaid cavities and the condenser, a valve stem attached to said diaphragmand provided with a passageway establishing communication between theother of said cavities and the said one chamber which communicates withthe outlet of the evaporator, a valve seat between said chambers, and avalve element carried b-y said stem and operable in cooperation withsaid seat to establish and to prevent communication between V,adriaticasaid chambers through movement of the stem by actuation of the diaphragmin response to pressure conditions created on opposite sides of thediaphragm by operation of said selectively controllable communicationmeans.

5. In combination with a refrigeration system of the type having acompressor, a condenser, a restrictor and an evaporator; means operableto control the iiow of refrigerant through the evaporator comprising avalve body provided with two intercommunicating chambers, onecommunicating with the outlet of the evaporator and the otherCommunicating with the inlet of the compressor, a diaphragm enclosed insaid body and cooperating with portions thereof to dene a cavity to oneside of the diaphragm and a cavity to the other side of the diaphragm,selectively controllable communication means between one of saidcavities and the condenser, a valve stem attached to said diaphragm andprovided with a passageway establishing communication between the otherof said cavities and the said one chamber which communicates with theoutlet of the evaporator, a valve seat between said chambers, a valveelement carried by said stem and operable in cooperation with said seatto establish and to prevent communication between said chambers throughmovement of the stem by actuation of the diaphragm in response topressure conditions created on opposite sides of the diaphragm byoperation of said selectively controllable communication means, and acontinuously open passage operable, when said valve element is moved toprevent communication between said chambers, substantially to by-passthe restrictor and to deliver refrigerant owing from the evaporator backto the inlet side of the compresser.

6. In a refrigeration system of the type having elements including acompressor, a condenser, a restrictor, an evaporator, and conduit meansincluding suction and feed lines connecting said elements in series flowcircuit, means operable to interrupt normal ow of refrigerant from theevaporator through the suction line to the compressor and to establishmodied ilow of refrigerant from the discharge side of the compressorthrough said suction line and to the evaporator, said means comprising avalve body interposed between sections of the suction line and providedwith two chambers one of which is connected with the suction linesection leading from the evaporator and the other of which is connectedwith the suction line section leading to the compressor, a pressureoperated diaphragm enclosed in said valve body, a valve member carriedby said diaphragm and operable to establish and to prevent communicationbetween said chambers, means in said valve body establishingcommunication between said one chamber and one side of said diaphragm,means in said valve member establishing communication between said otherchamber and the other side of said diaphragm, and a continuously openpassage operable, when said modified iiow is established, substantiallyto by-pass the restrictor and to deliver refrigerant owing from theevaporator back to the inlet side of the compressor.

References Cited in the file 0f this patent UNITED STATES PATENTS NumberName Date 1,863,427 Warren June 14, 1932 2,398,775 Beckley Apr. 23, 19462,451,385 Groat Oct. 12, 1948

